Exposed: the seven
great medical myths
Not to be believed
Drink at least eight glasses of water a day
Reading in dim light ruins your eyesight
We only use 10 per cent of our brains
Hair and fingernails continue to grow after death
Shaving causes hair to grow back faster or coarser
Mobile phones are dangerous in hospitals
Eating turkey makes people drowsy
They are among medicine's most widely held beliefs – drinking eight glasses of water a day is essential for health, shaving hair makes it grow back coarser, reading in a dim light ruins eyesight. Yet despite their popularity, they are myths.